Abstract

Many complex oxides with only nonvolatile constituents do not have a wide growth window in conventional molecular beam epitaxy(MBE) approaches, which makes it difficult to obtain stoichiometric films. Here it is shown that a growth window in which the stoichiometry is self-regulating can be achieved for films by using a hybrid MBE approach that uses a volatile metal-organic source for Ti, titanium tetra isopropoxide (TTIP). The growth window widens and shifts to higher TTIP/Sr flux ratios with increasing temperature, showing that it is related to the desorption of the volatile TTIP. We demonstrate stoichiometric, highly perfect, insulating films. The approach can be adapted for the growth of other complex oxides that previously were believed to have no wide MBEgrowth window.

Received 22 June 2009Accepted 29 June 2009Published online 23 July 2009

Acknowledgments:

The authors thank Nick Wright for some of the AFM studies and Tom Mates for the SIMS analysis. This research was supported by the National Science Foundation through the UCSB MRL (Award No. DMR 05-20415) and by DOE (Grant No. DE-FG02-06ER45994). Acquisition of the oxide MBE system was made possible through the NSF MRI program under Grant No. NSF DMR-0619698.